1. Field
The invention is concerned primarily with the recovering and sensing of sweat induced by iontophoresis for diagnosing the presence of cystic fibrosis in children or adults, especially the heretofore neglected area of obtaining and sensing sweat of newborn infants, but is also concerned with the sensing of sweat however induced or recovered from an area of a person's skin that is usually selected in advance.
2. State of the Art
Webster U.S. Pat. No. 4,383,529 and Webster et al. U.S. Pat. No. 4,542,751, both assigned to Wescor, Inc., Logan, Utah, disclose and describe in detail what have become standard devices and standard procedures for this diagnostic area of medical practice.
Thus, in Webster et al. U.S. Pat. No. 4,542,751 a sweat-collection device having a shallowly concave, sweat-collecting surface is applied to a patient's skin over an area that has been stimulated by iontophoresis. A length of flexible, plastic tubing has one end connected to an axial bore through which such plastic tubing extends for receiving a sample of sweat to be transferred to sweat-analyzing equipment. A strap secured to opposite ends of the sweat-collection device enables such device to be securely held in place against and covering a selected area of skin of a person to be diagnosed, which skin area has been previously subjected to iontophoresis for inducing sweating of that portion of the person's skin.
For iontophoresis prior to application of the above-referenced sweat-collection device, a pair of iontophoretic electrode devices are employed in accordance with Webster U.S. Pat. No. 4,383,529, thereby inducing sweating at the selected area of the person's skin. Such iontophoretic electrode devices may be and usually are mutually similar for convenience, but one is electrically positive for supplying the sweat-causing ions and the other electrically negative for completing an electrical circuit. At least the positive electrode device comprises a receptacle for holding an agar gel disc carrying an iontophoretic drug (usually pilocarpine). The agar gel disc has an exposed surface for contacting the selected area of skin and an opposite surface in electrical contact with an electrically positive electrode, so that the drug is applied to the thereby covered area of skin for stimulating the sweat glands of such area of skin. The other, an electrically negative electrode device, is conveniently the same, except for being electrically negative rather than positive and may be left in place or may be removed following sweat recovery. In any event, the electrically positive electrode device is replaced by the sweat-collecting device of Webster et al. U.S. Pat. No. 4,542,751 for collecting the induced sweat to be analyzed for diagnostic purposes.